A Tel Aviv magistrate issued a 15-day detention order today for five Palestinian Arabs who startled throngs of bathers here Saturday morning when they landed on the beach in an outboard motorboat. The men, who claimed they came from Alexandria and professed peaceful intentions, have been under interrogation as suspected terrorists.

Police believe they may have abandoned a terrorist mission at the last minute and decided to surrender. The bizarre incident has resulted in increased security measures along the miles of Tel Aviv’s beaches which were shown not to be invulnerable to invasion by sea.

According to eye-witnesses, the boat, about 15 feet long, driven by a powerful Chrysler outboard motor, came out of the west at high speed heading directly for the shore at about 9 a.m. local time. It made its way between scores of pleasure boats and swimmers enjoying the warm, sunny weather of the Rosh Hashanah weekend. It was not until the craft beached itself opposite the Plaza Hotel in the heart of Tel Aviv’s fashionable seashore district that spectators noticed Arabic inscriptions on the hull.

Some people on the beach panicked and ran. Others summoned police. The five occupants of the boat shouted “Salam” (peace) and in an apparently jolly mood began distributing bottles of whiskey and cigarettes from a suitcase to the crowd that gathered around the boat. Police appeared promptly but their inspection of the craft yielded neither arms, explosives nor narcotics. Some eye-witnesses claimed they saw the men throw something into the sea before they landed. A Tel Aviv couple aboard a pleasure boat claimed the speedboat had tried to ram their yacht but was driven off by a flare-gun.

CHANGE THEIR STORIES

The surprise visitors, all of dark complexion and seemingly in good humor, aroused suspicion as to their intentions when they changed the story given to police. They said at first that they were Palestinian seamen living in Alexandria who stole a motorboat in order to escape induction into the PLO forces fighting in Lebanon. They said they ran out of fuel on the high seas but were taken in tow by a Turkish vessel which sold them sufficient petrol to reach Tel Aviv.

Later on, however, they said they were on their way to visit relatives in the Gaza Strip. Three of the men said they were originally from Gaza and the others claimed to be from El Arish in northern Sinai.

Although both stories seemed credible, police suspect that the men may have had a sinister purpose and used the Turkish vessel as a shield to avoid detection by Israeli radar. The Turkish ship was slow, causing the motorboat to reach Tel Aviv in broad daylight, thus aborting a possible terrorist mission, some authorities believe. The boat itself had a very low freeboard–about 15 inches–and could easily have slipped under the radar screen. Moreover, it would have aroused no suspicion among the many other motorboats and yachts cruising off the Tel Aviv beach Saturday.

Some political circles have theorized that the incident was timed to coincide with the Palestinian terrorist attack on a Damascus hotel Saturday during which 90 persons were held hostage. It was intended to demonstrate the ability of the Palestinians to strike at two distant targets at the same time or, in some bizarre fashion, to show alleged Israeli-Syrian collusion against the Palestinians, the circles said.